Display refrigerator accessory



Feb. 18, 1936. 4

G. J. HOPKINS DI SPLAY REFRIGERATOR ACCESSORY Filed Jan. 29, 1934 2SheetsSheet l George [lop/(ins duel/wai Feb. 18, 1936. H Ns 2,030,923

DISPLAY REFRIGERATOR ACCES SORY Filed Jan. 29, 1934 2 Sheets-Sheet 2 ZZZLi li 2 (II I I, IiIi I I;

glwuentoz Patented Feb. 18, 1936 DISPLAY REFRIGERATOR ACCESSORY GeorgeJ. Hopkins, Kendallville, Ind., assignor to McCray Refrigerator Company,Kendallville, Ind., a corporation of Indiana Application January 29,1934, Serial No. 708,816

1 Claim.

The present invention relates to display refrigerator accessori s andmore particularly to drip pans designed for disposition below therefrigerating coils of refrigerators to catch the drip of n 5 moisturecondensation therefrom.

The principal objects of the invention are to provide a drip pan of thecharacter above indicated whose under surf-ace is composed of a materialtending to prevent moisture condensation l0 thereon; to provide such adrip pan whose under surface tends to prevent moisture condensation frompiling up in increasing quantities; to provide such a drip pan whoseunder surfaceis of a rough character tending to prevent moisturecondensation thereon from running together into larger drops tothereafter fall onto the food displayed within the interior of therefrigerator; and, to provide such a drip pan whose under surface isdisposed at such an angle that the surface tension of condensed moisturethereon. tends to prevent a flow of the moisture of condensation intolarger drops.

It is a well known fact that the air within a.

refrigerator is maintained; at a temperature of substantiallythat cf therefrigerating coils. In certain types of refrigerators, and particularlythose known as the display type, the refrigerating coils are disposedwithin the case longitudinally thereof and near the under side of itstop. Warm air rushing into the refrigerator when the doors thereof areopened is laden with a certain amount of moisture. The warm airimpinging on the cold refrigerating coils causes moisture to condenseand as these drops of water pile up in increasing quantities, they formlarger drops which subsequently fall from the refrigerating coils intothe interior of the case.

To catch these drops of water thus falling from the refrigerating coils,refrigerator manufacturers have located drip pans below the coils whichcarry off the falling drops of water. These drip pans have been made ofmetal such as of galvanized iron and the like but the objection offalling drops of water has not been completely solved since the underside of such a drip pan itself, which is of course at the temperature ofthe interior of the refrigerating case, likewise causes moisturecondensation to gather and thereafter drop onto the displayed food. Itis likewise known that metal has relatively high heat conductivity, thetable of thermal conductivity showing that a metallic surface has a heatconductivity of 750 B. t. u.s per square foot per degree per hour perinch of thickness. Any heat therefore that impinges upon the metallicsurface of such a metal drip pan is rapidly dissi- I pated to thesurrounding metallic area and when it is remembered that for every poundof water 1000 B. t. u.s must be removed to condense it from its vaporstate to its liquid state,.a great 5 amount of heat is taken up by thismetal drip pan. Thus it will be seen that inasmuch as the entire surfaceof the drip pan is within a narrow'range of the temperature of theinterior ofthe case, vapor in the inrushing warm air impinging on 10 thesurface of the drip pan will be condensed thereon because its surface isbelow: the dew point of the inrushing outside air. The problem is thus Inot to prevent moisture condensation for this is impossible as long asthe interior case temperature is below the dew point of the inrushingoutside air; the problem is to minimize thismoisture condensation on theunder surface of the drip pan to such an extent that the drops which doform will not pile up in increasing quantities to 20 thereafter fallinto the case interior.

Many materials have a heatconductivity flow of less than 25 B. t. u.sper square foot per de-, I gree per hour per inch of thickness, twomaterials particularly notedfrom the table of thermal con- 25ductivity-rubber and woodhaving approximately 1 B. t. u. flow per squarefoot per degree per hour per inch of thickness. Thus itwill be seen thatheat applied to such a surface'tends to flow relatively very slowly ascompared or 30 contrasted With heat applied to a metallic surface. Sincea certain amount of heat is liberated with every particle of moisturethat is condensed from the inrushing outside moisture laden air, thisliberation of heat raisesthe temperature of 35 the surface on which themoisture or vapor condenses or is deposited. But since the heat flowthrough rubber, wood and other materialshaving a small heat conductivityflow is relatively negligible as compared with metal, the heat tends 40to remain in the spot where it is liberated, maintaining the temperatureof that area at a higher level than that of the surrounding area.Subsequent condensation or piling up at the heated point is thuscurtailed. Thus it will be seen that although moisture will condenseupon the sur- 7 face of the rubber, wood or other material having arelatively low heat conductivity flow, the amount of moisture depositedon the under sur- 5 face of the drip pan will be very much less than itwould be in instances of a metallic under surface. Certain othermaterials, such as fibre compositions and the like, are of courseadaptable for use as drip pans, it being understood that 55 the rubbercoated drip pan herein shown and; described is merely exemplary.

It is likewise the problem to prevent such drops of moisture as docondense on the underside of the drip pan, formed from material with arelatively low heat conductivity flow, from running together to formlarger drops to thereupon fall into the inside of the display case. Theweight of a drop of water resolves itself into two compo-- nents-oneparallel with the plane of the drip pan and the other perpendicularthereto. These two forces are of course opposed by the well known force"surface tension. This force of surface tension is even'g'reater ininstances where a rough surface is used. Thus a forty-five degree angleslope of the bottom side of the drip pan is theo-- retically preferablethough not always practicable for space saving reasons. But any slopetends to prevent directly dripping of the condensed moisture, andparticularly in instances where the surface is rough such as a rubbersurface.

Illustrative embodiments of the invention are shown in the accompanyingdrawings, wherein:

Figure 1 is a. front elevational view of a display refrigerator, aportion thereof being broken away on line l--l of Figure 2 to bettershow parts of the interior thereof;

Figure 2 is an enlarged sectional view on line 2-2 of Figure 1;

Figure 3 is an enlarged sectional view thereof on line 3-3 of Figure 1;

Figure 4 is a sectional view on line 4-4 of ure 3;

Figure 5 is a fragmentary sectional view of the drip pan per se;

Figure 6 is a fragmentary view, that portion in section being on line6-6 of Figure 5;

Figure 7 is an enlarged view of a modified form of drip pan; and

Figure 8 is a sectional view thereof on line 8-8 of Figure 7.

Referring then to the drawings in which like parts of the structure aredesignated by the same numerals in the several views, a refrigerator,here shown as of the'display type, comprises the base I, front panels 2,3, ends 4, 5, top 6, rear sliding doors I, 8 giving access to itsinterior, and triple spaced panes of'glass 9, l0, and II permitting foodwithin thecase to be viewed by prospective purchasers.

A plurality of refrigerating coils I 2 running longitudinally of thecase are suspended below the under side of the top of the case in anysuitable manner as by a plurality of spaced hangers l3 secured to theunder side of the top of the case as by'the bolts H.

A pair of trough-shaped drip pans of the-character illustrated inFigures 1 to 6 inclusive are suspended below the refrigerating coils forthe entire length of the coils as bythe spaced hangers l5 to catch thedrip of moisture condensation falling from the coils and comprise ametallic upper surface iii of galvanized iron or the like, slopingtoward the end of the case, secured to the wood strips i! as by thehanger screws l8. A drain apron I9 is supported at the adjacent ends ofthe drip pan as best seen in Figures 4, 5 and drain conduits areprovided at the end of each drip pan to carry away the water fallingtherein,

covered by a roughened rubber coating 22, all as best illustrated inFigure 5. This rubber coated pan is secured to the wood strip as by thescrews 23.

As heretofore suggested, the under surface of the drip pan of theinstant invention is composed of a material. having arelatively-negligible heat conductivity flowas compared with that of ametallic under surface, and although the under surface 22 of the drippan is here illustrated as of roughened rubber, it will be understoodthat other materials having a heat conductivity flow of less than 25 B.t. u.s per square foot per degree per hour per inch of thickness givesatisfactory results. As further suggested herein, the opposite lengthsof the trough-shaped drip panare prefposed members 25, 26 disposedbeneath the re-' frigerating coils and secured to hangers 21 in spacedrelation to each other adjacent their inner' longitudinalsides. A fiatmetallic pan 28 is suspended below the spaced opening between themembers 25, 26 and parallel thereto by means oi brackets 29 which arepreferably spot welded to the upper surface thereof and are detachablyhooked over the hangers 21, as best seen in Figure 8.

A second metallic fiat pan 30 having a roughened rubber coating 3|embraces the pan 28 and its wooden base 32 to which both are secured asby the screws 33. The drip of moisture condensation from the coils fallsonto the members 25 or 26 from which it runs to the pan 28 which carriesthe water away in a manner similarto that described in connection withthe form of drip pan shown in Figure 5.

It will thus be seen that a novel type of drip pan for use incatching-the drip of moisture conprovided with an under surface formedof a ma-' terial which tends to prevent moisture condensation thereonbut also tends to prevent the piling up of the moisture in increasingquantities on its under surface to thereafter run together and fall ontothe food displayedwithin the refrigerator.

While but several embodiments of this invention have been herein shownand described, it will be understood that details of the constructionshown may be altered or omitted without departing from the spirit ofthis invention as defined by the following claim.

I claim:

A drip pan adapted for disposition below a refrigerating coil having anunder roughened surface of a material with a heat conductivity flow ofless than two B. t. u.s per square foot per degree per hour per inch ofthickness;

GEORGE J. HOPKINS.

